<?php

/*

 * This file is part of Twig.

 *

 * (c) 2009 Fabien Potencier

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

/**

 * Twig_NodeVisitor_Sandbox implements sandboxing.

 *

 * @package    twig

 * @author     Fabien Potencier <fabien@symfony.com>

 */

class Twig_NodeVisitor_Sandbox implements Twig_NodeVisitorInterface

{

    protected $inAModule = false;

    protected $tags;

    protected $filters;

    protected $functions;

    /**

     * Called before child nodes are visited.

     *

     * @param Twig_NodeInterface $node The node to visit

     * @param Twig_Environment   $env  The Twig environment instance

     *

     * @param Twig_NodeInterface The modified node

     */

    public function enterNode(Twig_NodeInterface $node, Twig_Environment $env)

    {

        if ($node instanceof Twig_Node_Module) {

            $this->inAModule = true;

            $this->tags = array();

            $this->filters = array();

            $this->functions = array();

            return $node;

        } elseif ($this->inAModule) {

            // look for tags

            if ($node->getNodeTag()) {

                $this->tags[] = $node->getNodeTag();

            }

            // look for filters

            if ($node instanceof Twig_Node_Expression_Filter) {

                $this->filters[] = $node->getNode('filter')->getAttribute('value');

            }

            // look for functions

            if ($node instanceof Twig_Node_Expression_Function) {

                $this->functions[] = $node->getNode('name')->getAttribute('name');

            }

            // wrap print to check __toString() calls

            if ($node instanceof Twig_Node_Print) {

                return new Twig_Node_SandboxedPrint($node->getNode('expr'), $node->getLine(), $node->getNodeTag());

            }

        }

        return $node;

    }

    /**

     * Called after child nodes are visited.

     *

     * @param Twig_NodeInterface $node The node to visit

     * @param Twig_Environment   $env  The Twig environment instance

     *

     * @param Twig_NodeInterface The modified node

     */

    public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env)

    {

        if ($node instanceof Twig_Node_Module) {

            $this->inAModule = false;

            return new Twig_Node_SandboxedModule($node, array_unique($this->filters), array_unique($this->tags), array_unique($this->functions));

        }

        return $node;

    }

    /**

     * {@inheritdoc}

     */

    public function getPriority()

    {

        return 0;

    }

}